Genome-wide Association Study of Kernel Black Point Resistance in Chinese Wheat Landraces

Abstract

Black point (BP) disease of wheat has become a noticeable problem in China. The symptoms are brown to black in color around the wheat kernel embryo or in the endosperm, resulting in a significant reduction of wheat grain quality. Here, we evaluated 272 Chinese wheat landraces for BP reaction and performed a genome-wide association study (GWAS) to identify BP resistance quantitative trait loci (QTL) in five field environments without artificial inoculation. The BP incidence data showed continuous distributions and had low to moderate correlations between environments (r = 0.094 – 0.314). Among the 272 landraces, 11 had 0.1% to 4.9%, 144 had 5% to 14.9%, and 100 had 15% to 29.9%, and 17 had over 30% incidence. We found three resistant accessions: WH094 (3.33%), AS661463 (2.67%), and AS661231 (2.67%), which can be used in breeding programs to enhance BP resistance. We identified 11 QTL, which explained 8.22% to 10.99% phenotypic BP variation and mapped them to eight wheat chromosomes. Three of the QTL were novel. The molecular markers for the BP resistance could facilitate molecular breeding for developing BP resistant cultivars.